Calculate line tension for accurate construction layout. Model spans, loads, and limits with clear outputs. Download reports, reduce risk, and keep crews aligned today.
A quick reference set you can try in the form above.
| Span (m) | Weight (kg/m) | Diameter (mm) | Wind (N/m²) | Ice (mm) | Target sag (m) | Strength (kN) | Safety factor |
|---|---|---|---|---|---|---|---|
| 60 | 1.25 | 12 | 0 | 0 | 1.80 | 35 | 2.5 |
| 80 | 1.60 | 14 | 650 | 5 | 2.30 | 45 | 3.0 |
This tool uses a parabolic sag approximation with a resultant distributed load per length. Let L be span length, w be resultant load (N/m), H be horizontal tension (N), and f be sag (m).
When adjustment is enabled, a simplified conductor state equation is applied to estimate the new horizontal tension after temperature and load changes. The solution is found numerically.
Stringing tension controls sag, clearance, and the loads transferred into blocks, travelers, and structures. On a 60 m span with a 1.25 kg/m conductor, typical settings produce several kilonewtons of horizontal tension. This calculator converts your field control—target sag or set tension—into support tension so the crew can verify temporary works and hardware remain within planned limits.
Field conditions are rarely “weight only.” The tool builds a resultant load per meter using vertical weight plus optional ice, combined with lateral wind. Ice weight is computed from thickness and density (often near 900 kg/m³), and wind load is pressure multiplied by the outside diameter (including ice). The reported components help reviewers confirm assumptions match the method statement.
Sag follows a parabolic approximation: it rises with span squared and falls as horizontal tension increases. For the same load, an 80 m span can show about 1.8× the sag of a 60 m span at equal tension, so long crossings need conservative inputs. Support tension adds the vertical component, which usually exceeds the horizontal value.
Strength checks should use an allowable, not the rated value. Enter rated tensile strength and a safety factor (commonly 2.0–3.0 for temporary operations) to obtain an allowable support tension. The utilization badge highlights “near limit” and “over limit” cases so you can adjust sag targets, revise load inputs, or update the pull plan before mobilizing.
Temperature shifts tension because the conductor expands and contracts. When enabled, the optional adjustment uses elasticity, area, and thermal expansion to estimate horizontal tension at a target temperature and load case. This supports planning for day swings, seasonal checks, and revised wind or ice scenarios. Confirm final settings with calibrated equipment and project standards. Document results for QA and share with the site supervisor.
Use sag when clearance targets or sag charts are controlling. Use tension when the pull plan specifies a set value from a dynamometer or puller setting. The calculator converts between the two using the same load case.
Horizontal tension acts along the span. Support tension is the resultant at the structure, combining horizontal tension with the vertical component from the distributed load. Support tension is typically higher and should be checked against allowables.
Wind load per meter is computed as wind pressure (N/m²) multiplied by outside diameter (m). It adds a lateral component that increases the resultant load and therefore increases both sag (for fixed tension) and support tension.
Ice is modeled as a cylindrical layer around the conductor. The calculator increases outside diameter by twice the ice thickness, computes the annular area, multiplies by ice density to get kg/m, then converts to N/m using gravity.
Enable it when you need an estimate of horizontal tension at a different temperature or load case after the stringing condition is known. Provide elasticity, area, and thermal expansion. Treat the output as planning guidance and verify with project procedures.
Use the value specified by your method statement, client standard, or temporary works design. Many projects apply a factor in the 2.0–3.0 range for temporary operations, but requirements vary by utility and equipment.
Exports include the key reported inputs and calculated outputs: span, resultant load, horizontal tension, sag, support tension, and allowable/utilization when provided. Save exports with pull logs and calibration records for traceable QA documentation.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.